Compressor oil pump with filter

ABSTRACT

A hermetic compressor having a vertical crankshaft overlying a sump of lubricating oil. The lower end of the crankshaft is journalled in an oil pump housing. A sandwich of a superimposed cover plate, filter plate, thrust bearing back-up plate and thrust bearing plate underlies the crankshaft and is secured to the pump housing. An impeller in the crankshaft discharges oil through the filter and into a passage in the lower end of the crankshaft to lubricate the gas compressor.

United States Patent 1191 Hannibal June 3, 1975 COMPRESSOR OIL PUMP WITH FILTER 3.250,46l 5/1966 Parker 411/902 Inventor: y B. Hannibal, Tecumseh, Mich 3,664,46l 5/1972 Leffers 184/616 [73] Assignee: Tecumseh Products Company, Primary ExaminerRichard C. Pinkham Tecumseh, Mich. Assistant Examiner-Marvin Siskind Attorney, Agent, or Firm-Barnes, Kisselle, Raisch & [22] Flled. Mar. 21, 1974 Cheats [21] Appl. No.: 453,280

[57] ABSTRACT [52 US. Cl. l84/6.l6; 417/368; 184/624; A hermetic Compressor having a vertical crankshaft 1 4/3 overlying a sump of lubricating oil. The lower end of 511 161.11 .1616, 1/10 the crankshaft isjoumalled in an oil p p musing- A [58] Field 61 Search 184/616, 6.18, 6.24, 31; sandwich of a superimposed cover plate, filter Plate, 413/ 9; 417/902 3 3 9 372 3 thrust bearing back-up plate and thrust bearing plate underlies the crankshaft and is secured to the pump [56 References Cited housing. An impeller in the crankshaft discharges oil UNITED STATES PATENTS through the filter and into a passage in the lower end of the crankshaft to lubricate the gas compressor. 2,312,596 3/1943 SmIth l84/6.l8 5437 5/1958 Boynton 184/616 12 Claims, 3 Drawing Figures Will/- COMPRESSOR OIL PUMP WITH FILTER This invention relates to compressor lubricating systems and more particularly to a hermetic compressor oil pump and filter device.

Objects of this invention are to provide an improved compressor oil pump and filter device which decreases clogging of the filter and is of rugged and durable construction, service and maintenance free and economical to manufacture and assemble.

These and other objects, features and advantages of this invention will be apparent from the following description, appended claims and accompanying drawings in which:

FIG. 1 is a fragmentary side view of a hermetic compressor embodying this invention with a portion of the shell broken away and part of a gas compressor therein shown in section to illustrate the component parts of the oil pump and filter device.

FIG. 2 is an enlarged end view of the oil pump and filter device of FIG. 1.

FIG. 3 is an exploded and enlarged sectional view on line 3-3 of FIG, 2.

Referring in detail to the drawings, FIG. 1 illustrates a hermetic compressor embodying this invention with a single cylinder gas compressor 12 driven by an electric motor (not shown) both hermetically enclosed in an outer shell 14. Gas compressor 12 has a cylinder block and frame 16 with a vertical crankshaft l8 journalled for rotation therein which is driven by the motor to reciprocate a piston 20 slidably received in a cylinder 22. Piston 20 is operably connected to crankshaft 18 by a connecting rod 24 with an end cap 26 secured thereto by bolts 28.

Gas compressor 12 has an improved oil pump and filter 30 of the present invention partially submerged in a pool of lubricating oil 32 received in a sump formed by the bottom of casing 14. Compressor 12 has an outboard bearing 34 secured to frame 16 by cap screws 36 (FIG. 2) in which the lower end of crankshaft 18 is journalled for rotation by a crankshaft bearing journal 38 of the crankshaft, which journal is received in a sleeve bearing 40 press fit in a bore of outboard bearing 34.

In accordance with one feature of the present invention, the pump-filter device 30 incudes a four-piece sandwich subassembly consisting of a cover or back-up plate 42, a filter 44, a bearing back-up thrust plate 46 and a thrust bearing plate 48. These parts are secured in superimposed relationship to the lower face of outboard bearing 34 by a pair of screws 50 extending through a pair of diametrically spaced holes 52 in each of the plates. Outboard bearing 34 thus also serves as part of the housing of pump-filter device 30. Plates 46 and 48 have an identical layout with a central portion 54 and 54' respectively. Central portion 54' provides a wear surface on which the lower end of crankshaft l8 bears and portion 54 provides an underlying thrust support. Preferably, bearing plate 48 is made of a low friction, highly wear resistant material such as Norplex No. 825N asbestos phenolic plastic available from Norplex Fabricators of LaCrosse, Wisconsin, and back-up plate 46 is made of steel. Filter 44 is preferably in the form of a thin, flat porous sheet made of a microporous membrane material such as the 5 micron membrane material No. RV-7020 available from GAF Corporation, Industrial Products Division, of Warren, Michigan. However, filter 44 may be made of other suitable material which will function as a filter or screen to separate particulate contaminants from the lubricating oil.

Cover plate 42 in cooperation with a cavity 56 in lower face of outboard bearing 34 defines in assembly an enclosed chamber 58 (FIG. 1) with filter plate 44 extending thereacross to serve as a partition which divides chamber 58 into an upper chamber 580 and a lower chamber 58b. A pump impeller 60 is disposed within upper chamber 58a and is formed in the lower end of crankshaft 18 by an annular groove 62 in the end face of bearing journal 38 and by a plurality of circumferentially spaced radially extending bore holes 64 which communicate with both groove 62 and upper chamber 58a and serve as centrifugal impeller blades. Groove 62 in cooperation with bearing plate 48 defines an annular inlet chamber in impeller 60. Plates 42, 44, 46 and 48 each have a pair of diametrically spaced slots 66a, 66b, 66c and 66d respectively extending therethrough which are registered to form a pair of axially extending passageways which connect the inlet chamber 62 with the pool of oil 32. Oil to lubricate gas compressor 12 is discharged from the pump into a crankshaft passage 68 which extends coaxially of crankshaft 18 from the lower end thereof upwardly to suitable discharge passages or ports (not shown).

Passage 68 is connected to the lower chamber 58b of the pump via an axial passageway defined by registering center holes 70a, 70b and 70c extending through plates 44, 46 and 48 respectively. Filter plate 44 is clamped in sealing engagement about its periphery with the outer marginal portion of plate 46 by the lip 42a of plate 42. Likewise, the central portion of filter plate 44 is urged into sealing engagement with the central portion of thrust plate 46 by a pair of flanges 72, one surrounding each of the holes 52, and by a flange 74 surrounding the slots 66a. This assures that oil discharged into upper chamber 580 must pass through filter plate 44 and into lower chamber 58b before flowing via passageway 70a, 70b and 70c into passage 68.

In operation of hermetic compressor 10, the motor rotates crankshaft 18 which both reciprocates piston 20 and rotates pump impeller 60 to supply lubricating oil to the bearings of the gas pump along the flow path 76 indicated by the arrows in FIG. 3. Thus, the rotation of impeller 60 creates a suction which draws lubricating oil 32 from the bottom of shell 14 upwardly through ports 66a, 66b, 66c and 66d into groove 62, and causes the oil to be centrifuged radially outwardly therefrom via passages 64 into upper chamber 58a at a higher pressure. The pressurized oil in the upper chamber 580 then passes downwardly through exposed areas of filter plate 44 into lower chamber 58b and is discharged upwardly therefrom via coaxial holes 70a, 70b and 70c in plates 44, 46 and 48 respectively into crankshaft passage 68 so as to flow upwardly therein to lubricate the gas compressor.

From the foregoing description, it will be noted that filter plate 44 is located on the discharge or high pressure side of the pump, which has been found to decrease the tendency of the filter to become clogged or plugged. This in turn insures a longer service life. The sandwich subassembly arrangement of the thrust bearing plate 48, thrust plate 46, filter plate 44 and cover plate 42, as well as the use of cavities, grooves and passages in outboard bearing 34 and crankshaft 18, pro vides a compressor pump and filter device of economical construction and assembly due to a reduction in parts and the plate configurations which accommodate these parts to being manufactured by low cost mass production stamping processes. Moreover, assembly is facilitated by the stack-up arrangement of the pump and filter parts.

What I claim:

1. An oil pump and filter device for a gas compressor comprising in combination a crankshaft with a lubricating oil passage extending generally axially therein from one end thereof, a sump for lubricating oil disposed adjacent the crankshaft, a housing with said one end of the crankshaft journalled therein, a discharge chamber formed in cooperation with said housing adjacent said one end of said crankshaft, a centrifugal impeller received in said discharge chamber and fixed to said crankshaft for rotation therewith, said impeller having an inlet chamber communicating with both lubricating oil in the sump and said discharge chamber for discharging oil into said discharge chamber at a higher pressure than the oil in the sump in response to rotation of said impeller by the crankshaft, and a filter positioned in flow communication with said discharge chamber for filtering therethrough the flow of oil after it is discharged from said impeller and before entering the axial oil passage of the crankshaft.

2. The oil pump and filter device of claim 1 which also comprises a cover plate having a wall spaced from said housing and forming in cooperation therewith said discharge chamber, said cover plate being secured to said housing.

3. The oil pump and filter device of claim 2 which also comprises a thrust bearing plate received in said first chamber with the said one end of said crankshaft bearing thereon, said thrust bearing plate being interposed between said housing and said cover plate.

4. The oil pump and filter device of claim 3 wherein said filter comprises a generally flat plate of porous material interposed between said thrust bearing plate and said cover plate.

5. The oil pump and filter device of claim 4 which also comprises a thrust bearing back-up plate in said discharge chamber interposed between said thrust bearing plate and said filter plate.

6. The oil pump and filter device of claim 4 wherein said thrust bearing plate, filter plate and cover plate are superimposed in a sandwich assembly secured to said housing.

7. The oil pump and filter device of claim 1 which also comprises a thrust bearing plate received in said first chamber with said one end of said crankshaft bearing thereon.

8. The oil pump and filter device of claim 7 which also comprises a thrust bearing back-up plate in said first chamber interposed between said thrust bearing plate and said cover plate.

9. The oil pump and filter device of claim 8 wherein said thrust bearing plate, thrust bearing backup plate, filter plate and cover plate are superimposed in a sandwich assembly secured to said housing.

10. The oil pump and filter device of claim 1 wherein said filter comprises a generally fiat plate of a porous material.

11. The oil pump and filter device of claim 2 wherein said filter comprises a generally flat plate of porous material interposed between said housing and said cover plate.

12. The oil pump and filter device of claim 1 wherein said oil passage opens into an end face of said crankshaft in a central portion thereof, and said impeller comprises a groove in said end face encircling said opening of said oil passage therethrough and at least one passage extending through the lower end portion of said crankshaft radially between said groove and said discharge chamber. 

1. An oil pump and filter device for a gas compressor comprising in combination a crankshaft with a lubricating oil passage extending generally axially therein from one end thereof, a sump for lubricating oil disposed adjacent the crankshaft, a housing with said one end of the crankshaft journalled therein, a discharge chamber formed in cooperation with said housing adjacent said one end of said crankshaft, a centrifugal impeller received in said discharge chamber and fixed to said crankshaft for rotation therewith, said impeller having an inlet chamber communicating with both lubricating oil in the sump and said discharge chamber for discharging oil into said discharge chamber at a higher pressure than the oil in the sump in response to rotation of said impeller by the crankshaft, and a filter positioned in flow communication with said discharge chamber for filtering therethrough the flow of oil after it is discharged from said impeller and before entering the axial oil passage of the crankshaft.
 1. An oil pump and filter device for a gas compressor comprising in combination a crankshaft with a lubricating oil passage extending generally axially therein from one end thereof, a sump for lubricating oil disposed adjacent the crankshaft, a housing with said one end of the crankshaft journalled therein, a discharge chamber formed in cooperation with said housing adjacent said one end of said crankshaft, a centrifugal impeller received in said discharge chamber and fixed to said crankshaft for rotation therewith, said impeller having an inlet chamber communicating with both lubricating oil in the sump and said discharge chamber for discharging oil into said discharge chamber at a higher pressure than the oil in the sump in response to rotation of said impeller by the crankshaft, and a filter positioned in flow communication with said discharge chamber for filtering therethrough the flow of oil after it is discharged from said impeller and before entering the axial oil passage of the crankshaft.
 2. The oil pump and filter device of claim 1 which also comprises a cover plate having a wall spaced from said housing and forming in cooperation therewith said discharge chamber, said cover plate being secured to said housing.
 3. The oil pump and filter device of claim 2 which also comprises a thrust bearing plate received in said first chamber with the said one end of said crankshaft bearing thereon, said thrust bearing plate being interposed between said housing and said cover plate.
 4. The oil pump and filter device of claim 3 wherein said filter comprises a generally flat plate of porous material interposed between said thrust bearing plate and said cover plate.
 5. The oil pump and filter device of claim 4 which also comprises a thrust bearing back-up plate in said discharge chamber interposed between said thrust bearing plate and said filter plate.
 6. The oil pump and filter device of claim 4 wherein said thrust bearing plate, filter plate and cover plate are superimposed in a sandwich assembly secured to said housing.
 7. The oil pump and filter device of claim 1 which also comprises a thrust bearing plate received in said first chamber with said one end of said crankshaft bearing thereon.
 8. The oil pump and filter device of claim 7 which also comprises a thrust bearing back-up plate in said first chamber interposed between said thrust bearing plate and said cover plate.
 9. The oil pump and filter device of claim 8 wherein said thrust bearing plate, thrust bearing backup plate, filter plate and cover plate are superimposed in a sandwich assembly secured to said housing.
 10. The oil pump and filter device of claim 1 wherein said filter comprises a generally flat plate of a porous material.
 11. The oil pump and filter device of claim 2 wherein said filter comprises a generally flat plate of porous material interposed between said housing and said cover plate. 